The present invention relates to a portable information terminal apparatus for signal communication by radio, the apparatus being implemented illustratively as a pager which receives a radio signal from a radio station, ascertains that the signal is addressed thereto, alerts the user to the incoming signal by means of sound, light and/or mechanical vibration, and displays the received information.
There exist portable information terminal apparatuses each serving as a terminal of a communication network. They have been commercialized with diverse structures and functions to meet today's varied and rapidly expanding demands in the field of telecommunications.
One typical portable information terminal apparatus is the pager for receiving radio signals. In its infancy, the pager was a terminal that beeped upon receipt of a call signal from a radio station. Typically, a user carrying such a pager would be in a location away from wired telephones. On receiving a radio call signal issued by someone via a radio station, the pager alerted the user to call back from the nearest wired telephone.
Then came the new generation of pagers capable of receiving not only simple call signals but also signals containing information via radio stations. The type of pager used extensively today is the one which has a liquid crystal display panel capable of displaying a message retrieved from the incoming signal carrying information.
More functions have been added to today's pagers. One such function implemented extensively is what is known as a vibrator function that replaces beeping sound when necessary. This function is used advantageously outdoors and locations where sound-based alert is not helpful. Such locations include bustling streets where ambient noise may hamper the user from hearing an alerting sound, and theaters and conference rooms where silence is the norm in the audience and a beep will disrupt the atmosphere. The user may select manually either beeping sound or the vibrator function as alerting means.
To offer more convenience for the user, the pager may have a watch mode allowing its liquid crystal display (LCD) panel to indicate a date and a time of day in numerics. A growing number of portable information terminal apparatuses other than the pager are also incorporating the watch mode, with an LCD panel showing likewise the date and the time of day in numerics.
Portable information terminal apparatuses offering the watch mode also provide a watch setting mode. For example, this is a mode in which a user sets up a date and a time of day before operating the apparatus for the day or for the first time. The watch setting mode is used not only to initialize the time indication but also to correct an error of time after an extended period of use and to change displayed numerics for specific purposes.
With a portable information terminal apparatus set in the watch setting mode for changing displayed numerics, it is necessary to designate one of two displays to be changed: the date, or the time of day. When the target display is selected, it is then necessary to perform operations to increment or decrement the currently displayed numerics to get the desired ones.
Such operations are typically carried out on conventional portable information terminal apparatuses as follows: an upward and a downward arrow key are provided in the vertical direction along an edge of a liquid crystal display (LCD) panel, and a leftward and a rightward arrow key are furnished horizontally along another edge of the LCD panel. The leftward and rightward arrow keys are operated to select a target numeric among those displayed on the LCD panel. With the target numeric selected, the upward or downward arrow key is operated respectively to increment or decrement the numeric indication until a desired number is reached.
In addition, the above-mentioned portable information terminal apparatuses need to be small in overall size for carryable use by users. Hence there need to minimize the number of keys located on the apparatus panel.
Conventional portable information terminal apparatuses of the above type, however, have many operation keys that prove to be constraints on the effort to reduce their total size. The large number of parts making up the terminal can lead to higher cost and detract from the ease of operation.
An alternative to the provision of a plurality of discrete keys has presented itself in the form of a rotary input device and a rotating/pushbutton type input device. They are typically implemented as a jog dial or a rotary encoder. A single rotary input device has a rotating disk-like dial that is turned clockwise or counterclockwise in desired amounts and at desired angles in order to generate two kinds of input signal. The adoption of the dial-equipped rotary input device has reduced key-occupied space and contributed to making the terminal smaller as a whole.
However, the above rotary input device, designed to generate two kinds of input signal when rotated clockwise and counterclockwise, is not always efficient in operation.
Take for example the changing of a date indication on the display screen. When the related art arrow keys are used to update the displayed numerics, the increment and decrement of the indication obviously related to the upward and downward arrow keys respectively. That is not the case with the dial-equipped rotary input device; the increment and decrement of the numerics displayed do not obviously relate to the directions of the rotary operation part which is set in the rotary input device. That is, it is not quite sure for users which way to turn the dial for increment or decrement.
Meanwhile, rotating type sound volume adjusting devices known as rheostats are used extensively for acoustic equipments. These devices are similar in operation to the above-described dial-equipped rotary input device.
The rheostat is a dial-like device characterized by the traditionally established association between the direction of rotation and the increase or decrease of sound volume. Specifically, turning the dial clockwise increases the sound level; turning it counterclockwise turns down the sound. Where rotary input devices are used to increment or decrement a physical quantity, they may disregard the tradition at the risk of losing operative consistency with similarly manipulated rheostats.
If there is a large difference in numerics between the currently displayed date and a desired date on the terminal, updating operations must be carried out a large number of times. The procedure is a time-consuming chore that does not help to promote the ease of use.